1. Field of the Invention
The present invention relates to a device comprising an integrated circuit and integrated MEMS structure that uses a barrier to prevent transmission of environmental and process contaminants, and a method of fabricating an integrated circuit and MEMS device using a barrier to prevent transmission of contaminants.
2. Discussion of the Related Art
In general, MEMS devices use either a sensor device with sensing circuitry or an actuation device with drive circuitry to detect or produce physical phenomenon. In one embodiment, the MEMS device is formed having a sensor device that makes use of a moveable membrane, and the sensing circuitry is commonly formed using typical semiconductor-type fabrication processes. In a typical integrated circuit, the circuitry is formed on a die and a seal ring barrier is formed along outer edges of the die to prevent contamination of the circuitry. Although underlying oxide/nitride layers may be exposed to various environmental and process contaminants during the die singulation process, the seal ring barrier prevents any of the contaminants from contaminating the circuitry.
In addition, incorporation of MEMS devices and associated driving/sensing circuitry on a single die requires formation of a barrier in order to prevent ionic contaminant migration from the MEMS device, as well as moisture and contaminants from the surrounding atmosphere, to the circuitry. Specifically, ionic contaminants and moisture may adversely affect electrical properties of the circuit components and cause changes in circuit performance relative to contamination levels, thereby rendering the integrated circuit/MEMS device inoperable. Accordingly, a barrier is required to physically separate the MEMS device from the driving/sensing circuitry that may allow for passage of electrical signals and at the same time prevent migration of contaminants into the MEMS device.